POS0932 ULTRASOUND-DEFINED GRADE I SYNOVITIS IN PATIENTS WITH INFLAMMATORY-SUSPECTED ARTHRALGIA AND ITS ROLE IN DIAGNOSIS A YEAR LATER
Authors: A. M. Ruiz Bejerano, A. Corral Bote, J. Arroyo Palomo, B. A. Blanco Cáceres
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Musculoeskeletal ultrasound is frequently used in several rheumatology units to detect subclinical inflammation in patients with joint symptoms suspected for progression to inflammatory arthritis. <h3>Objectives</h3> The main goal is to investigate the correlation between synovitis grade I (EULAR-OMERACT combined score) and the diagnosis of established inflammatory arthropathy that is carried out after a follow-up period of one year since the first ultrasound findings. The assessment is done in an ultrasound-specialized unit of a Rheumatology Department <h3>Methods</h3> We conducted a descriptive, retrospective and unicentric study where 135 patients were selected from the ultrasound-specialized unit of our rheumatology department from July 2018 to December 2021. Patients that presented synovitis grade 0,2 and/or 3 on combined score were excluded. Collected baseline data included age, sex, immunological profile, acute phase reactants and physical examination previous to the ultrasound findings, as well as the diagnosis made by the rheumatologist a year after said findings. To achieve that, the patients are divided into two groups: those who were diagnosed with inflammatory arthropathy and those who were not. In addition, non-parametric statistical tests for comparing means were used. <h3>Results</h3> The mean age was 55 years and 75% of the patients were females. At the beginning, clinical examination revealed a median of one tender joints and none swollen. Previous diagnosis of psoriasis was present in 18 (13,3%) patients while inflammatory bowel disease was present in 6 patients (4,4%). Of the 135 patients, after a year follow-up, 46 (34,1%) received the diagnosis of inflammatory arthropaty after a follow-up of one year: 15 (32,6%) psoriatic arthritis, 8 (17,4%) rheumatoid arthritis, 8 (17,4%) undifferentiated arthritis, 4 (8,7%) spondyloarthritis, 4 (8,7%) calcium pyrophosphate dehydrate crystal-related joint disease, 3 (6,5%) reactive arthritis, 2 (4,3%) systemic sclerosis, 1 (2,2%) Sjögren syndrome and 1 (2,2%) polymyalgia rheumatica. Non-inflammatory arthropathies were also found 89 (65,9%), of which 64 (71,9%) were osteoarthritis, 20 (22,5%) Carpal tunnel syndrome and 5 (5,6%) had other soft tissue disease. In the group of patients who did not developed an autoimmune arthropathy, 3 were Rheumatoid factor-positive and 10 were AAN-positive, none of them were aCCP- positive; The HLA B-27 and Cw6 test resulted in 5 patients testing positive in HLA-B27 and none in Cw6. Among the group of patients that developed an inflammatory arthropathy the median of joints with ultrasound involvement was 2. Grade I power Doppler signal was detected in one case. 7 (15,2%) patients were RF- positive, and 6 (13%) aCCP-positive. AANs were positive in 13 cases (28,3%). There were no significant differences for clinical variables and acute phase reactants (Age, sex, SJC, TJC, RCP, ESR) between both groups. Comparing the immunological profile through a Fisher's exact test, we obtained a statistically significant association for RF (p=0,033), aCCP (p=0,001) and AAN (p=0,014) in the group who finally received the diagnosis of inflammatory arthropathy. No other significant differences were found (Total joints GSUS, total joints PDUS, HLA B27 and HLA Cw6) <h3>Conclusion</h3> Despite the limitations and possible statistical bias that might appear in a retrospective study, there are a remarkable number of patients with ultrasound-defined grade I synovitis who develop inflammatory arthropaty a year later. Rheumatoid factor, aCCP and AAN positivity were the only factors statistically associated with progression. <h3>References</h3> [1]Van den Berg R et al. What is the value of musculoskeletal ultrasound in patients presenting with arthralgia to predict inflammatory arthritis development? A systematic literature review. <i>Arthritis Research &amp; Therapy</i> (2018) 20:228. [2]Kawashiri S et al. Combination of ultrasound power Doppler-verified synovitis and seropositivity accurately identifies patients with early-stage rheumatoid arthritis <i>Int J Rheum Dis.</i> 2019;1–10. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.